MANILA, April 29 (Xinhua) -- There is no incidence yet of swine flu in the Philippines, but government agencies are on high alert against the disease that has spread from North America to Asia and other continents, officials said on Wednesday.

"The Philippines is on high alert and is moving quickly to defend our borders against threats of emerging infectious diseases," Health Secretary Francisco Duque said at the 4th Asia-Pacific BioSafety Association Conference held in Manila.

Following the World Health Organization's (WHO) alert that the outbreak of swine flu has escalated to a public-health emergency of international concern, the Philippine Department of Health immediately has taken a series bio-security measures in all airports to prevent the entry of the virus.

A total of 11 thermal scanners have been deployed in six international airports in the country to screen possible signs and symptoms of the disease. Fifteen doctors and 27 medical assistants specifically assigned to handle such cases are on round-the-clock duty in all the terminals of Manila's Ninoy Aquino International Airport. Any passengers confirmed to have fever will be immediately quarantined and brought to a Research Institute of Tropical Medicine.

Duque told reporters that the health department is planning to place more thermal scanners not only in airports but also in seaports to prevent the H1N1 swine flu strain from entering the Southeast Asian country.

Swine flu is a highly contagious acute respiratory disease of pigs, caused by one of several swine influenza A viruses. Outbreaks in pigs occur year round, with an increased incidence in the fall and winter in temperate zones. Swine flu viruses are most commonly of the H1N1 subtype, but other subtypes (e.g., H1N2, H3N1, H3N2) are also circulating in pigs.

H1N1 is the subtype that has killed 159 people out of over 2,000 suspected cases in Mexico. Besides, more than 100 cases -- suspected or confirmed -- of human infection have been found in 14 other countries, including one suspected case in the South Korean.

Officials said that there has been no case of swine flu reported in the Philippines, but media reports say hundreds of hogs died recently in the northern province of Pangasinan. Doctors say the pigs died of a deadly disease called "poor reproductive and respiratory syndrome" not swine flu as suspected by some local media. Some samples of organ specimen from swine casualties have been sent for laboratory confirmation to the Philippine Animal Health Center under the Bureau of Animal Industry in Manila and the result is expected to come out later this week.

Officials pledged to make the situation transparent to the public and advised the people not to panic over the swine flu epidemic, boasting that the government had succeeded in keeping the country free from avian flu, and managed to keep cases of Severe Acute Respiratory Syndrome (SARS) to a minimum.

"Our record in preventing SARS and avian flu from coming to the country...have been successful and based on that experience, the government is pulling no stops to ensure that our people will be protected," Press Secretary Cerge Remonde said in a news briefing.

Meanwhile, the health authorities issued an advisory suggesting that people should cover their mouths and noses when coughing or sneezing, wash their hands regularly with soap and refrain from kissing, hugging and shaking hands.

The health chief, as well as the country's Department of Foreign Affairs, discouraged Filipinos to travel to swine flu-hit countries like Mexico and the United States although there is no ban on traveling to those countries.

For its part, the country's Department of Agriculture ordered to temporarily suspend pork imports from affected areas in Mexico, the United States and Canada, adding that it is also closely monitoring reports of swine flu incidences in France, New Zealand, South Korea, and Spain to find out if there is a need to expand the temporary suspension of pork imports from these areas. Agriculture Secretary Arthur Yap said that the temporary ban covers only specific areas of the three countries, not the whole.

The Philippines does not import pork from Mexico but imports about 20,000 metric tons annually from the United States and about the same amount from Canada. Yap said the Philippines will maintain the import ban as a precautionary measure despite the latest pronouncement by the World Organization for Animal Health that "there is no evidence that this virus is transmitted by food."

In spite of all efforts government agencies have made, Duque said that the authorities "can't give 100-percent assurance that it (the virus) won't get to the Philippines."

"We should be alarmed and take precautions because we are now at alert level 4 as announced by the WHO," he said. Level 4 means there is already human-to-human transmission of the virus, while alert levels 5 and 6 mean there is widespread human-to-human transmission, according to the health chief.

"We made sure the stockpile of anti-flu medicine is adequate," he said, adding the government has about 600,000 capsules for 60,000 possible swine flu cases. The government is also ensuring adequate supply of masks for frontline health workers, who would also be provided with other forms of protection.